cas...@gmail.com wrote:
On Thursday, October 25, 2012 7:56:25 AM UTC-7, Charles Hixson wrote:
In Python3 is there any good way to count the number of on bits in an
integer (after an& operation)?
You may want to look at gmpy2[1] and the popcount() function.
Alternatively, is there any VERY li
On Thursday, October 25, 2012 7:56:25 AM UTC-7, Charles Hixson wrote:
> In Python3 is there any good way to count the number of on bits in an
> integer (after an & operation)?
You may want to look at gmpy2[1] and the popcount() function.
>
> Alternatively, is there any VERY light-weight impleme
On 2012-10-25, Ian Kelly wrote:
> On Thu, Oct 25, 2012 at 2:00 PM, Neil Cerutti
> wrote:
>> Yes indeed! Python string operations are fast enough and its
>> arithmetic slow enough that I no longer assume I can beat a
>> neat lexicographical solution. Try defeating the following
>> with arithmetic:
On 25-10-12 16:47, Charles Hixson wrote:
> In Python3 is there any good way to count the number of on bits in an
> integer (after an & operation)?
> Alternatively, is there any VERY light-weight implementation of a bit
> set? I'd prefer to use integers, as I'm probably going to need
> thousands of
On Thu, 25 Oct 2012 14:20:00 -0600, Ian Kelly wrote:
> On Thu, Oct 25, 2012 at 2:00 PM, Neil Cerutti wrote:
>> Yes indeed! Python string operations are fast enough and its arithmetic
>> slow enough that I no longer assume I can beat a neat lexicographical
>> solution. Try defeating the following
On 25/10/2012 17:08, Charles Hixson wrote:
On 10/25/2012 08:57 AM, Steven D'Aprano wrote:
On Fri, 26 Oct 2012 02:31:53 +1100, Chris Angelico wrote:
On Fri, Oct 26, 2012 at 2:25 AM, Christian Heimes
wrote:
Simple, easy, faster than a Python loop but not very elegant:
bin(number).count("1"
In Python3 is there any good way to count the number of on bits in an
integer (after an & operation)?
Alternatively, is there any VERY light-weight implementation of a bit
set? I'd prefer to use integers, as I'm probably going to need
thousands of these, if the tests work out. But before I can
On 10/25/2012 08:57 AM, Steven D'Aprano wrote:
On Fri, 26 Oct 2012 02:31:53 +1100, Chris Angelico wrote:
On Fri, Oct 26, 2012 at 2:25 AM, Christian Heimes
wrote:
Simple, easy, faster than a Python loop but not very elegant:
bin(number).count("1")
Unlikely to be fast.
Oh I don't know abo
In Python3 is there any good way to count the number of on bits in an
integer (after an & operation)?
Alternatively, is there any VERY light-weight implementation of a bit
set? I'd prefer to use integers, as I'm probably going to need
thousands of these, if the tests work out. But before I can
On Thu, Oct 25, 2012 at 2:00 PM, Neil Cerutti wrote:
> Yes indeed! Python string operations are fast enough and its
> arithmetic slow enough that I no longer assume I can beat a neat
> lexicographical solution. Try defeating the following with
> arithmetic:
>
> def is_palindrom(n):
>s = str(n)
On 10/25/2012 12:13 PM, rusi wrote:
On Oct 25, 7:56 pm, Charles Hixson wrote:
In Python3 is there any good way to count the number of on bits in an
integer (after an & operation)?
Alternatively, is there any VERY light-weight implementation of a bit
set? I'd prefer to use integers, as I'm prob
On 2012-10-25, Neil Cerutti wrote:
> Try defeating the following with arithmetic:
>
> def is_palindrom(n):
>s = str(n)
>return s = s[::-1]
Sorry for the typos. It should've been:
def is_palindrome(n):
s = str(n)
return s == s[::-1]
--
Neil Cerutti
--
http://mail.python.org/mailm
On 2012-10-25, Steven D'Aprano wrote:
> On Fri, 26 Oct 2012 02:31:53 +1100, Chris Angelico wrote:
>> On Fri, Oct 26, 2012 at 2:25 AM, Christian Heimes
>>
>> wrote:
>>> Simple, easy, faster than a Python loop but not very elegant:
>>>
>>>bin(number).count("1")
>>
>> Unlikely to be fast.
>
> O
Chris Angelico's suggestion:
>>> bitcount = bytes(bin(i).count("1") for i in range(256))
>>> t = Timer('sum(number.to_bytes((number.bit_length() + 7) // 8,'
... '"little").translate(bitcount))',
... setup='from __main__ import bitcount; number=2**10001-1')
>>> min(t.repeat(number=1, repeat=7)
On Thu, Oct 25, 2012 at 11:25 AM, Christian Gollwitzer wrote:
> There is a very geeky algorithm with only a few integer operations.
>
> Checkout
> http://graphics.stanford.edu/~seander/bithacks.html#CountBitsSet64
>
> for a C version. Maybe the same thing is equally fast when ported to Python.
It
Am 25.10.12 16:47, schrieb Charles Hixson:
In Python3 is there any good way to count the number of on bits in an
integer (after an & operation)?
Alternatively, is there any VERY light-weight implementation of a bit
set? I'd prefer to use integers, as I'm probably going to need
thousands of these
On Thu, 25 Oct 2012 09:17:40 -0700, rusi wrote:
> On Oct 25, 8:57 pm, Steven D'Aprano +comp.lang.pyt...@pearwood.info> wrote:
>> On Fri, 26 Oct 2012 02:31:53 +1100, Chris Angelico wrote:
>> > On Fri, Oct 26, 2012 at 2:25 AM, Christian Heimes
>> > wrote:
>> >> Simple, easy, faster than a Python l
On Oct 25, 9:30 pm, Chris Angelico wrote:
> On Fri, Oct 26, 2012 at 3:17 AM, rusi wrote:
> > On Oct 25, 8:57 pm, Steven D'Aprano > +comp.lang.pyt...@pearwood.info> wrote:
> >> py> min(t.repeat(number=1, repeat=7))
> >> 0.6819710731506348
> >> py> min(t.repeat(number=100, repeat=7))
> >> 4.14
On 25/10/2012 17:29, Chris Angelico wrote:
On Fri, Oct 26, 2012 at 3:17 AM, rusi wrote:
On Oct 25, 8:57 pm, Steven D'Aprano wrote:
py> min(t.repeat(number=1, repeat=7))
0.6819710731506348
py> min(t.repeat(number=100, repeat=7))
4.141788959503174
That makes the "inelegant" solution using
On Thu, Oct 25, 2012 at 9:24 AM, Mark Lawrence wrote:
> On 25/10/2012 15:47, Charles Hixson wrote:
>
>> In Python3 is there any good way to count the number of on bits in an
>> integer (after an & operation)?
>> Alternatively, is there any VERY light-weight implementation of a bit
>> set? I'd pre
On Fri, Oct 26, 2012 at 3:17 AM, rusi wrote:
> On Oct 25, 8:57 pm, Steven D'Aprano +comp.lang.pyt...@pearwood.info> wrote:
>> py> min(t.repeat(number=1, repeat=7))
>> 0.6819710731506348
>> py> min(t.repeat(number=100, repeat=7))
>> 4.141788959503174
>>
>> That makes the "inelegant" solution u
On 25/10/2012 15:47, Charles Hixson wrote:
In Python3 is there any good way to count the number of on bits in an
integer (after an & operation)?
Alternatively, is there any VERY light-weight implementation of a bit
set? I'd prefer to use integers, as I'm probably going to need
thousands of these
On Oct 25, 8:57 pm, Steven D'Aprano wrote:
> On Fri, 26 Oct 2012 02:31:53 +1100, Chris Angelico wrote:
> > On Fri, Oct 26, 2012 at 2:25 AM, Christian Heimes
> > wrote:
> >> Simple, easy, faster than a Python loop but not very elegant:
>
> >> bin(number).count("1")
>
> > Unlikely to be fast.
>
On Oct 25, 7:56 pm, Charles Hixson wrote:
> In Python3 is there any good way to count the number of on bits in an
> integer (after an & operation)?
> Alternatively, is there any VERY light-weight implementation of a bit
> set? I'd prefer to use integers, as I'm probably going to need
> thousands
On Fri, 26 Oct 2012 02:31:53 +1100, Chris Angelico wrote:
> On Fri, Oct 26, 2012 at 2:25 AM, Christian Heimes
> wrote:
>> Simple, easy, faster than a Python loop but not very elegant:
>>
>>bin(number).count("1")
>
> Unlikely to be fast.
Oh I don't know about that. Here's some timing results
On Fri, Oct 26, 2012 at 2:25 AM, Christian Heimes wrote:
> Simple, easy, faster than a Python loop but not very elegant:
>
>bin(number).count("1")
Unlikely to be fast.
What you may want is some sort of hybrid loop/lookup approach. Do you
know what your highest bit number is going to be? For
Am 25.10.2012 16:47, schrieb Charles Hixson:
> In Python3 is there any good way to count the number of on bits in an
> integer (after an & operation)?
Simple, easy, faster than a Python loop but not very elegant:
bin(number).count("1")
Christian
--
http://mail.python.org/mailman/listinfo/
On 2012-10-25 15:47, Charles Hixson wrote:
In Python3 is there any good way to count the number of on bits in an
integer (after an & operation)?
Alternatively, is there any VERY light-weight implementation of a bit
set? I'd prefer to use integers, as I'm probably going to need
thousands of these
In Python3 is there any good way to count the number of on bits in an
integer (after an & operation)?
Alternatively, is there any VERY light-weight implementation of a bit
set? I'd prefer to use integers, as I'm probably going to need
thousands of these, if the tests work out. But before I can
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